Hmm, something wrong here !
- Thread starter SimonH2
- Start date
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Interesting and (to me) rather surprising - I must have a look at one!
I'm not sure that is necessarily a safe/reasonable assumption. If the switch did precede the fuse, they could wire the indicator to the downstream end of the fuse. I guess it depends upon what they intend the indicator should indicate (and what the switch should switch). Again, I'll have a look at some when I get a chance.
Kind Regards, John
I've now had a quick look on my shelves. I can't find an MK one, but all the switched FCUs I can find which consist of a single moulded unit (Crabtree, Volex, 'MB' and some of uncertain make!) fairly clearly have the switch before the fuse.
Seemingly not in the (uncertain make!) ones I've just examined.
Closest to the OP, I've also found a generic Varilight 'Fitting Instructions' sheet. Under "Fuse holder used with double pole switch" it indicates that one should wire with the switch before the fuse - i.e. not with the link as pre-wired in the OP case.
Kind Regards, John
That would indeed be the case for the usual "one piece" FCUs. In the case of these "grid" versions, it would be impossible without adding at least one extra terminal to the switch to feed the indicator. I'd assume the indicator will be interal to the switch and wired directly across it's output terminals - so for these, the fuse would need to precede the switch for the indicator to work sensibly (ie indicate "output live").
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That's all clearly true if one 'fabricates' a switched FCU using (literally or effectively) 'standalone' switch/indicator and fuse carrier grid/modular modules. I would suggest that if one really wanted to fully emulate a 'one piece' switched FCU+indicator withh such modules, one really would have to use three modules - the third one being an indicator (I've done that in my time).
Kind Regards, John
That's the beauty of one of these:
You can use it unswitched if you want..
What's scary though is that you just know that at some time in the next 20-odd years life of that accessory, some of them are going to lose those links and end up being wired as unfused switches.....
Or even unfused, should that take your fancyThat's the beauty of one of these:
You can use it unswitched if you want..
However, in both cases there are cheaper ways of achieving those single functionalities!Kind Regards, John
Damn - a bit too slow with the edit.
True - and if your talking 'scary', a sufficiently accomplished idiot could, of course, wire one of these 'two-part' switched FCUs with the fuse in the neutral (either before or after the switch)!
Kind Regards, John
But that applies (almost) just as equally to a standard "one piece" FCU - nothing to stop someone swapping L & N on the input and as far as testing goes "it works doesn't it ?"
Interestingly, my mate brought in another unit and I've had a look at the destructions - not that they are very detailed !
They do indeed show "FUSE HOLDER USED WITH DOUBLE POLE SWITCH" wired with the fuse holder after the switch - ie different to how they supply the FCU pre-wired.
The diagram is the same as in this sheet - though the sheet itself is different.
They do indeed show "FUSE HOLDER USED WITH DOUBLE POLE SWITCH" wired with the fuse holder after the switch - ie different to how they supply the FCU pre-wired.
The diagram is the same as in this sheet - though the sheet itself is different.
Yes, that's true. I was thinking that the aforementioned idiot may be more likely to get 'internal wiring' wrong than simply reversing the L&N feeds - but I suppose that may be a rash assumption!
Kind Regards, John
In summary (so far), then, all the 'one piece' FCUs I found on my shelf (including a couple with indicators) had the switcg before the fuse, and the instructions that you and I have found indicate switch before fuse for 'two piece' ones. Hence, apart from your one with the pre-installed link, we haven't yet heard of any which have the fuse first - apart from a (so far unconfirmed) statement that MK ones do that. Has anyone got (or seen) any switched FCUs (or associated instructions) with fuse before switch?
Kind Regards, John
well it was only an assumption based on the fact the neon is now in the head of the switch, rather than remote but i stand to be corrected
I have opened a mk logic fcu without a neon although unlike the logic plus range these had remote indicators.
And you know what the switch is before the fuse and the load output terminal connects to said fuse
I have opened a mk logic fcu without a neon although unlike the logic plus range these had remote indicators.
And you know what the switch is before the fuse and the load output terminal connects to said fuse
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